I'm still a little confused about the whole who Savitar is thing and time remnants and flash point, could you try and explain it if you have time?
It’s complicated in part because it’s discussed in canon as a closed time loop, similar to Eobard’s sort of paradoxical existence / time loop, and our brains don’t do so good with loops (and the Flash canon doesn’t really involve loops, it just pretends that it does, but it makes more sense to conceive of speedster time-travel as more linear and branching).
A simple explanation that I drew from to answer this came from ScreenRant so do check it out. But here’s what I’ve got, to the best of my current understanding.
First things first: Savitar’s and Cisco’s explanations.
Savitar says that Barry will create time remnants to kill Savitar, and all but one of them will die. That time remnant will be shunned because he’s not the “real” Barry, and moreover, this is after Iris is dead (I assume? It’s implied) so no one is really in an emotional state to be there for a time remnant confused about his own existence. He’s literally Barry, a grieving Barry, one who has lost everything and isolated himself and is all the darkest parts of himself. That’s the Barry who makes the time remnants to fight Savitar, and doesn’t think about the consequences of having one of them survive.
So this time remnant, we’ll call him Barry-S, he’s lost and confused and hurting just as bad as Barry, just as angry, and even worse. He sees that Barry has everything but shuns it: the love and acceptance of the people who he still has left. isolated, Barry-S sort of says “fuck this” and leaves. Presumably, time travels, heads to other dimensions, begins to build his suit, and over time creates this reputation as “the first speedster” for himself. Maybe we can conjecture that at first, he’s training, trying to go up against other speedsters to improve, finding the fastest people across time and dimensions so that he can get fast enough to stop Savitar, to fix all this. He’s still Barry, after all.
But like the parable of the Black Night, this White Night runs through the forest searching for his enemies for so long that his suit of armor becomes muddied and his heart bleak, and becomes what he sought to end and avenge. He slowly realizes his suit is becoming that of Savitar’s, as he builds it, and that his speed is truly becoming unparalleled after all, and what his reputation is becoming as the “God of Motion”. He sees where it’s going, and it grips his (cold, still grieving, bleak and heavy) heart. And he continues. Pushes on. Continues to fight and kill, becoming what ruined him.
Because it’s all he has left. It’s all he ever had. Was this pain, that Barry bore him into the world with. Memories of a life and an Iris that were never his, because they belonged to Barry, and not to Barry-S, not to the mere remnant.
So after… who knows how long. Weeks, centuries, time is totally relative to someone like that, he returns. Returns to 2021. That’s right. Returns to the Barry who created him to wreak his vengeance. Except that doesn’t go exactly as planned.
That Barry is waiting with a trap, the one built by Tracy to deal with Savitar’s suit. So when Barry-S arrives decked out in the suit, and he is trapped in the speedforce. Note that up until he was created, he and Barry had the same memories, so Barry must’ve gone to Tracy after the fiasco with the time remnants “mostly” dying, and likely Savitar ditched shortly after that, only to seemingly return later (to challenge Barry) once the trap was complete. Except it’s Barry-S returning.
I mean, it’s still “Savitar”, but he’s younger than the Savitar in 2017 who kills Iris. Barry-S hasn’t done that yet. He’s the younger version of Savitar except he’s run into the future, to 2021, to challenge Barry. And maybe it’s Barry-S and not the older Savitar because he kills his older self and takes his place. Maybe he has to, to be strong enough to face Barry, because maybe the older version of Savitar is too tired and weak and scarred after his own temporal loop, after being trapped in the speedforce for so long, and Barry-S needs to take his place and live out their destiny.
So Barry-S challenges Barry in 2021, and Barry-S gets trapped. He’s imprisoned and pissed. And going through hell in the speedforce, trapped inside that prison, likely reliving the moment Iris dies over and over.
And inside the speedforce trap, he realizes he has to escape. Maybe he’s eroding, or maybe that hasn’t happened yet. But it will. He has to close the loop in order to exist. It is a time loop, and unless he escapes and kills Iris, none of this ever happens, at least in this timeline. He has to escape, kill Iris, live to 2021… and then get killed by himself (his younger self), probably, unless he can change things.
So, somehow using the philosopher’s stone (I don’t have all the details on that front) and sheer force of will, he manages to appear to speedsters in the material world, to use his skills to gain acolytes, to see across the timelines Barry has created (like Flashpoint) and use them against him. Up until the point where he manages to finally escape from the speedforce.
At which point, it’s all going just like he remembers it did, back when he was Barry, when they were one and the same, before he was Barry-S, a remnant.
(Except maybe he doesn’t remember this… Barry is changing things now, after having run to the future. 2024!Barry hadn’t done that, so now we’re in a new timeline).
But to Savitar, Iris was dead before he was created, and he’ll kill her in order to close the loop and ensure he will create himself, become himself. Only this time, he intends to stay free after he does. To not become trapped ever again, and to not die in 2021 when he meets Barry-S, his past self who hasn’t yet been trapped and eroded.
(Or if he never did kill his older self, maybe he was always sort of free, after, given that it’s his past self that was trapped in the speedforce. But then, the rules of time travel don’t fully apply to him, and to be trapped in there might mean to be trapped at all points in time/existence - past, present, and future. Regardless of what it is, I would not be surprised.).
For the record, you can conceive of all these time jumps as creating slightly different unique timelines, and it’ll still sort of lead you to the same place, but that’s an added layer relative to what the show tried to give us.
But, that also explains why Barry killing himself now (or failing to create a remnant in the future) won’t necessarily “undo” Savitar as we know him now. The Savitar we know now came from a different timeline, was created already in that timeline, the same way Eobard was a time remnant from another timeline. Eobard died when his ancestor died in the current timeline because his existence was no longer confluent with the current timeline and the speedforce didn’t like it, but Barry-S may have hopped timelines so many times that’s become somewhat irrelevant, especially since he was created from a loop to begin with.
Final note: how this fits with Flashpoint?
It sort of does and sort of doesn’t. The point is mostly that when Barry mucked up the timeline as much as he did, he created a new timeline in which a different set of events happened than it otherwise would have. Savitar wasn’t an issue before he messed up the timeline, but when he did, he created a timeline in which Savitar and this time loop existed and have always existed. I can’t say exactly why, except maybe as a repercussion from selfish timetravel handed down by the semi-sentient speedforce or else because the existence of Savitar was/is predicated on the existence of multiple timelines that are connected only through the speedforce (philosopher’s stone) so splitting the timeline too much creates problems like him as some mercurial inevitable outcome.
Either way, way to go Barry.